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BIOL 3V00 - Exam 3: Cardiovascular
Terms in this set (67)
Describe the event that happens during ventricular systole?
The main event common in both is the opening of the semilunar valves (pulmonary valve in the right side and aortic valve in the left side)
The central circulation contains blood that is in what?
heart, lungs (pulmonary blood vessels)
At what age of the embryo's life does the heart begin to pump blood?
22nd day of gestation
What is cardiac output?
heart rate multiplied by the stroke volume and volume of blood being pumped by the heart per minute
Describe the course of impulse travel through the cardiac conduction system.
-pacemaker impulse (SA node)
-AV node impulse conduction
-AV bundle impulse conduction (bundle of His)
-Purkinje Fibers Impulse conduction
What is the SA node and what is the function?
-sinoatrial node, referred to as a pacemaker of heart, coordinates heart contractions
-located in upper wall of right atrium, it generates nerve impulses that travel throughout the heart wall causing both atria to contract
Briefly describe the pathway of the cardiac cell contraction.
1) An action potential, induced by the pacemaker cells in the sinoatrial (SA) and atrioventricular (AV) nodes, is conducted to contractile cardiomyocytes through gap junctions
2) Action potentials travel between sarcomeres (The smallest functional units of myofibril.) activating calcium channels in T-tubules, resulting in an influx of calcium ions into cardiomyocyte.
3) Calcium ions in the cytoplasm bind to troponin, troponin complex moves away from the actin-binding site, freeing up the actin to be bound by myosin and initiates contraction.
4) Myosin head binds ATP and pulls the actin filaments toward center of sarcomere, contracting muscle
5) Intracellular calcium is removed from SR, decreasing intracellular concentration, returning troponin complex to inhibitory state, effectively ending contraction as actin filaments return to initial position (muscle relax)
Describe the two periods of ventricular systole:
-isovolumetric contraction period
-the AV valves are closed and semilunar valves are closed; ventricles begin to contract. ventricular muscle initially shortens only a little, but intraventricular pressure rises sharply
-(ventricular) ejection period
-AV valves are closed and semilunar valves are open; pressure in left and right Ventricle exceed pressures in Aorta and Pulmonary Artery. Ejection is rapid at first, slowing down as systole progresses
What is the cardiac cycle? Describe its two parts: Systole and Diastole.
-rhythmic pumping of heart (0.8 seconds long) that is broken into two parts
-systole (ventricle contraction)
-diastole (ventricle relaxation)
Describe blood flow in the Vena Cava.
-Inferior Vena Cava = it carries deoxygenated blood from the lower half of the body to the right atrium of the heart. Clinical significance: blockage of the inferior vena cava is associated with DVT (blood clot)
-Superior Vena Cava = receives blood from the upper limbs, eyes, and neck, behind the lower border of the first right costal cartilage. Clinical significance: obstruction can lead to enlarged veins in the head and neck, and may also cause breathlessness, cough, chest pain, and difficulty swallowing
Cardiovascular disease accounts for nearly __________ of all deaths in the united states.
Calcific aortic stenosis causes __________ to flow
Most cases of congestive heart failure are due to __________
Define congestive heart failure and what it is caused by.
-CHF is generally defined as heart failure
-CHF occurs when the heart cannot generate sufficient output to meet the metabolic demands of the tissues
-CHF is caused by many conditions that damage cardiac muscle such as: coronary artery disease, heart attack, cardiomyopathy, other conditions that overwork the heart (high blood pressure, valve disease, thyroid disease, kidney disease, diabetes, or birth heart defects)
Define systolic dysfunction. What sort of diseases cause this dysfunction?
-systolic dysfunction is defined as a reduced ejection fraction due to inadequate myocardial contractile function
-ischemic heart disease
Define diastolic dysfunction. What sort of diseases cause this dysfunction?
-diastolic dysfunction is the inability of the heart to adequately relax and fill
-massive left ventricular hypertrophy
Describe the Frank-Starling mechanism.
-increased end-diastolic filling volumes dilate the heart
-cardiac myofiber stretching is increased
-these fibers contract more forcibly, thereby increasing cardiac output
Does compensated heart failure usually lead to decompensated heart failure? Explain.
-in compensated heart failure, the dilated ventricle is able to maintain cardiac output via the Frank-Starling mechanism
-this ventricular dilation comes at the expense of increased wall tension and amplifies the oxygen requirements of the myocardium
-eventually, the muscle fails and is no longer able to propel sufficient blood to meet needs of tissues and the patient develops decompensated heart failure
What are three mechanisms the cardiovascular system uses to compensate for reduced myocardial contractility or increased hemodynamics burden?
-the frank-starling mechanism
-activation of neurohumoral systems
-myocardial structural changes
What are the most common causes of right-sided heart failure?
-right heart failure usually is the consequence of left-sided heart failure
-pressure increase in the pulmonary circulation inevitably produces an increased burden on the right side of the heart
What is usually the earliest and most significant symptom of left-sided heart failure?
dyspnea (shortness of breath)
What are three clinical manifestations of left ventricular failure?
-a third heart sound (S3)
-fine rales at the lung bases
-pulmonary congestion and edema
-left atrial dilation
-decreased renal perfusion
What are three clinical manifestations of right ventricular heart failure?
-right atrial and ventricular dilation
In most cases of chronic cardiac decompensation, patients presents with __________
biventricular CHF, encompassing the clinical syndromes of both right-sided and left-sided heart failure
Describe Eisenmenger Syndrome.
-prolonged left-to-right shunting with volume and pressure overloads eventually causes pulmonary hypertension and secondarily right-sided pressures that exceed those on the left
-at that point, reversal of blood flow occurs, with resultant right-to-left shunting, and the development of cyanosis
-such reversal of flow and shunting of unoxygenated blood into the the systemic circulation is called Eisenmenger syndrome
Describe the three types of congenital atrial septal defects?
-Ostium Secundum ASDs (90% of ASDs) occur when the growth of the septum secundum is insufficient to occlude the second ostium
-Ostium Primum ASDs (accounting for 5% of these defects) occur at the lowest part of the atrial septum and can be associated with mitral and tricuspid valve abnormalities
-Sinus Venosus ASDs (accounting for another 5% of the cases) are located high in the atrial septum and often are accompanied by anomalous drainage of the pulmonary veins into the right atrium of superior vena cava
Describe the Tetralogy of Fallot.
-the four cardinal features are: (1) right ventricular outflow tract obstruction (pulmonary stenosis), (2) right ventricular hypertrophy, (3) VSD, (4) overriding of the VSD by the aorta
-the hemodynamic consequences of tetralogy of Fallot are right-to-left shunting, decreased pulmonary blood flow, and increased aortic volumes. the clinical severity largely depends on the degree of the pulmonary blood flow, and increased aortic volumes. the clinical severity largely depends on the degree of the pulmonary outflow obstruction
Describe infantile coarctation.
-"infantile" (preductal) coarctation is characterized by circumferential narrowing of the aortic segment between the left subclavian artery and the ductus arteriosus
-photo on review slide
Describe ischemic heart disease and list three clinical manifestations
-ischemic heart disease (IHD) is caused by myocardial ischemia
-acute myocardial infarction (MI)
-chronic IHD with CHF
-sudden cardiac death (SCD)
Describe angina pectoris and the variants of angina
-angina pectoris is an intermittent chest pain caused by transient, reversible myocardial ischemia. the pain is a consequence of the ischemia-induced release of adenosine, bradykinin, and other molecules that stimulate the autonomic afferents
-typical or stable angina
-prinzmetal or varient angina
Describe myocardial infarction as well as the clinical features of a classic MI.
-myocardial infarction (MI), also commonly referred to as "heart attack", is necrosis of heart muscle resulting from ischemia
-severe, crushing chest pain radiating to the neck, jaw, epigastrium, or left arm
-weak and rapid pulse
-myoglobin, cardiac troponins T and I, creatine kinase, and lactate dehydrogenase found in the blood
List five manifestations of arrhythmia.
-irregular rhythm with normal ventricular contraction
-chaotic depolarization without functional ventricular contraction (ventricular fibrillation)
Define the following vascular tumors and list their classification: capillary hemangioma, lymphangioma, glomus tumor, angiosarcoma, hemangioendothelioma
-capillary hemangioma, lymphangioma, and glomus tumor are benign vascular tumors
-angiosarcoma is a malignant tumor
-hemangioendotheliomas are low-grade malignant tumors
Describe bacillary angiomatosis.
-bacillary angiomatosis is typically found in AIDS patients and caused by Bartonella henselae
What percentage of cases will an angiography reveal a thrombus occulting the coronary artery after the onset of infarction?
-angiography performed within 4 hours of the onset of MI reveals coronary thrombosis in almost 90% of cases
__________ is the most common cause of death within the first few hours after a coronary artery occlusion.
__________ is currently the best biochemical indicator of a myocardial infarction
What is the most common cause of sudden cardiac death in adults?
-atherosclerotic coronary heart disease
-ischemic heart disease caused by thrombotic occlusion of atherosclerotic coronary arteries
Rheumatic endocarditis is the most common cause of __________.
-mitral stenosis, accounting for 99% of all classes
Fever, murmurs, embolic phenomena, and the ultrasonographic findings suggest the diagnosis of _________
Formation of thrombi and emboli arising from these thrombi account for the common and the most serious complications following __________
-prosthetic valve implantation
Congenital hypertrophic cardiomyopathy can result from the mutation of the gene encoding __________. List five proteins.
-myosin-binding protein C
-B-myosin heavy chain
-cardiomyopathy can result from the mutation of any one of the five proteins
Which of the following is the most common cardiac disease encountered in patients who have rheumatoid arthritis?
-fibrinous pericarditis often progresses to adhesive pericardial fibrosis
-adhesive pericardial fibrosis is the most common heart disease found in patients who have longstanding rheumatoid arthritis
The most common location of atrial septal defects is in the area of the
Endomyocardial catheter biopsy is the only reliable means of diagnosing __________.
-transplantation rejection in transplanted hearts
What is an adaptive response of the heart to systemic hypertensive heart disease?
Name the two categories of hypertensive heart disease.
-Systemic (left-sided) hypertensive heart disease
-Pulmonary (right-sided) heart disease (Cor pulmonale)
Myocyte hypertrophy increases the content of contractile proteins at the expense of what?
-compliance, impairing diastolic filling while increasing oxygen demand
Chronic Cor pulmonale is a result of what specific factors?
-chronic right ventricular pressure overload
Name some causes of acquired valvular heart disease?
-degeneration = calcification
-inflammatory processes = rheumatic heart disease
-infection = infective endocarditis
-changes secondary to myocardial disease
What type of valvular heart disease is a common degenerative age-related lesion?
-calcific aortic stenosis
Describe mitral valve prolapse and its primary form
-one or both mitral valve leaflets are enlarged, redundant, myxomatous, and floppy; they balloon back into the atrium during systole
Describe rheumatic fever.
-an acute inflammatory disease classically occurring in children after a group A streptococcal infection (usually pharyngitis)
What is seen microscopically in the acute phase of rheumatic fever?
-antischokow cells - "caterpillar cells"
Describe the Jones criteria? What are the Jones criteria?
-the constellation of findings to diagnose rheumatic fever
-erythema marginatum = skin rash
-sydenham chorea = purposeless movement
-subcutaneous nodules and/or migratory large joint polyarthritis
Describe the two types of infective endocarditis and the common bacteria associated with each:
-this type of infective endocarditis is caused by highly virulent organisms (staphylococcus aureus), typically seeding a previously normal valve to produce necrotizing, ulcerative and invasive infections
-this type of infective endocarditis is typically caused by moderate to low-virulence organisms (streptococcus viridians) seeding an abnormal or previously injured valve
Name the bacterial agents in the low virulence HACEK group of oral cavity commensals associated with infective endocarditis?
Describe nonbacterial thrombotic endocarditis
Describe endocarditis of systemic lupus erythematosus, and give another name for this disease.
-endocarditis that occurs in SLE and in antiphospholipid syndrome, presumably due to immune complex deposition
Carcinoid tumors elaborate bioactive products that can cause cardiac lesions. What are these products?
-tachykinins P and K
What are the two types of prosthetic heart valve?
-mechanical = rigid, synthetic
-bioprosthetic = chemically fixed animal tissue
What are the three main functional and pathologic patterns of cardiomyopathies? Briefly describe each.
-Dilated: characterized by gradual four chamber hypertrophy and dilation
-Hypertrophic: characterized by heavy, muscular, hyper contractile, poorly compliant hearts with poor diastolic relaxation
-Restrictive: characterized by a restriction of ventricular filling leading to reduced cardiac output; contractile function and ventricle size are normal
This protozoan, also associated with Chagas Disease, causes myocarditis in the majority of those infected with it?
Most cases of myocarditis in the United States are viral in origin. What are the most common pathogens responsible?
-Coxsackievirus A and B
What is the etiology of serous pericarditis?
-the etiology of serous pericarditis is usually unknown; however, it is characteristically non-bacterial
What are the most common causes of left-sided heart failure?
-ischemic heart disease (IHD)
-mitral or aortic valve disease
-primary diseases of the myocardium (e.g., amyloidosis)
What are two intracellular bacteria that kill the host cell through rapid replication and lysis?
stigella and E. coli
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